// Strategic-layer RNG interface.
//
// Every roll in the strategic simulation (tech-tree race gating, research completion,
// lab accidents, probabilistic jumps, ...) draws from one server-owned generator so that
// lockstep peers stay in sync. The sim formulas in this module never own a generator;
// they take an IRandom& so tests can inject a scripted sequence and the real engine can
// inject its MT19937-compatible generator (implemented elsewhere, under src/mars/).
#pragma once

#include <cstdint>

namespace sots::sim {

struct IRandom {
    virtual ~IRandom() = default;
    // Uniform float in [0, 1] INCLUSIVE: the generator's unit mapping divides by
    // 2^32 - 1, and the value is narrowed to a 32-bit float before any consumer
    // compares it (mars::rng::MT19937::next_float).
    virtual float NextFloat() = 0;
    // Uniform integer in [0, n] INCLUSIVE (mask-and-reject; the mask covers n, not
    // n - 1). n == 0 returns 0 and still consumes one word.
    virtual std::uint32_t NextIntInclusive(std::uint32_t n) = 0;
    // The raw tempered word, no mapping. A handful of sites take it directly -- the
    // random-unit-vector helper a failed probabilistic jump uses is one -- and a
    // reimplementation has to consume the same word to stay on the same stream.
    virtual std::uint32_t NextUInt32() = 0;
};

}  // namespace sots::sim